Parkes observations for project P1168 semester 2022OCTS_02

We have discovered seven pulsars in the globular cluster Terzan 1 with the Green Bank Telescope, the first pulsars to be found in this cluster. The discoveries include five fully-recycled millisecond pulsars (MSPs) with spin periods between 3 and 6 ms, an 11-ms MSP, and a pulsar with an unusually long spin period of 134 ms. Preliminary timing suggests that all seven are likely isolated pulsars, consistent with Terzan 1 being a core-collapsed globular cluster. The 134-ms pulsar is an especially interesting discovery in the context of pulsar formation via electron-capture rather than core-collapse supernovae. We propose three Parkes observations with the UWL receiver to test how well these pulsars can be timed at Parkes; the wide bandwidth will provide a balance of sensitivity at low frequencies and reduced scattering at high frequencies. If the pulsars are sufficiently bright to be timed, we will either request completing a full year of observations under continuing status or propose to continue the timing campaign in the next semester. In addition to timing, the proposed observations will also be searched for new pulsars.

本研究借助绿岸望远镜（Green Bank Telescope）在球状星团Terzan 1中发现7颗脉冲星，这是该星团内首次被观测到的脉冲星。此次发现包含5颗完全再循环的毫秒脉冲星（millisecond pulsars, MSPs），其自转周期介于3至6毫秒之间，另有1颗自转周期为11毫秒的毫秒脉冲星，以及1颗自转周期长达134毫秒的特殊脉冲星。初步计时分析显示，这7颗脉冲星均为孤立脉冲星，这与Terzan 1作为核塌缩球状星团的物理特性相符。这颗134毫秒脉冲星的发现具有特殊研究价值，其形成过程或通过电子俘获机制而非核塌缩超新星爆发实现。我们提议利用UWL接收机开展3次帕克斯（Parkes）望远镜观测，以测试这批脉冲星在帕克斯望远镜上的计时观测效果；该接收机的超宽带宽可在低频段维持高灵敏度的同时，于高频段降低星际散射效应。若这批脉冲星亮度足够支持计时观测，我们将申请以持续观测项目状态完成一整年的观测工作，或是申请在下一学期继续推进此项计时观测计划。除计时观测外，此次提议的观测还将同步开展新脉冲星的搜寻工作。